The present invention relates to an off-loader and, more particularly, to an off-loader which is adjustable to permit stacking of parts of a wide variety of different sizes, styles and materials, simultaneously, from a variable number of parallel lanes of parts and which can be used in conjunction with conveyors of different dimensions.
Basically, an off-loader is a materials handling device which takes a number of parts fed to it in succession from one surface, for instance a conveyor, and places the parts in a stack on a second surface, such as a stacking table or the like. Such a device is normally used at the output of an assembly line operation wherein partially or fully completed parts travel down a conveyor. The parts are taken off the conveyor in succession and placed on a table or the like for temporary storage, transfer to another assembly line station for further operations, or transfer to a packing station to permit packaging for shipment.
In the past, operations such as off-loading, which require simple repetitive movements, have been performed by unskilled or semi-skilled workers. However, rising labor costs have put increasing pressure on manufacturers to automate portions of assembly lines as much as is practical because the cost of capital equipment, spread over the lifetime of the machinery, is less than the aggregate costs associated with the labor required to perform the same operation over the same period.
Materials handling equipment can do things which workers cannot. Such equipment can be designed to work faster and more accurately than workers, move heavier loads than a worker can and perform repetitive operations without becoming bored or tired. Machines do not become ill or pregnant, require no fringe benefits, and do not unionize for collective bargaining purposes. Such machines can be specifically designed to perform well defined operations efficiently and productively.
However, machines of this type also have a major disadvantage. A machine can be designed to do a specific well defined task highly efficiently, but if the task changes, albeit slightly, the machine cannot adjust to this change and must be mechanically altered each time the task changes. Human beings, on the other hand, can modify their behavioral patterns to suit the situation. Thus, in certain instances, human labor has a great advantage over mechanized systems--versatility. Because conventional equipment lacks versatility, it has been difficult to produce equipment to automate certain operations in some industries because of wide variations in production techniques between different manufacturers and variations in a particular manufacturer's production system as different types of products are produced on the same line.
While it is recognized that versatility is required if a machinery manufacturer is to produce a machine with widespread application, building versatility into materials handling equipment is costly. In fact, building versatility into equipment can be so costly that the capital expenditure required for the equipment may be greater than the cost of the unskilled labor which can perform the same function, thereby contra-indicating the use of the machine.
While different industries demand different degrees of versatility in materials handling equipment, one type of industry, the clothing and softgoods manufacturing industry, has been particularly resistant to the widespread use of automated equipment. The reason for this resistance is clear when the nature of this industry is considered. Manufacturers in this industry tend to produce a single product, or a line of closely related products. For example, some manufacturers manufacture only men's shirts, while others manufacture only men's suits or ladies' outerwear. Thus, each manufacturer has a different type of production system suited to the particular product, or products, which it manufactures. For this reason, it is difficult for a materials handling equipment manufacturer to produce a single piece of equipment which can be readily adapted to the large number of different production systems which are used in the manufacture of the different types of clothing. In addition, each manufacturer must be able to produce parts, although similar in nature, in a large variety of different sizes, styles and fabrics. Thus, a piece of materials handling equipment which is purchased by such a manufacturer must be capable of operating successfully for products of a wide variety of different sizes, styles and fabrics without requiring substantial mechanical modification. Moreover, the equipment must be able to accommodate a variable number of different parallel lanes of parts simultaneously.
Theoretically, the operation of a piece of materials handling equipment, such as an off-loader, is quite simple: grasp parts in succession from a conveyor; move the parts from the conveyor to a different location and place the parts on a stack at the second location. However, in practice, to produce a commercially successful off-loader, the equipment manufacturer must produce a machine which is versatile enough to find industry-wide application in a wide variety of different production systems making different types of products, and, in addition, must be versatile enough such that a particular manufacturer can modify the machine to accommodate parts of different sizes, styles and fabrics and variable numbers of lanes of parts in an inexpensive and relatively rapid fashion.
It is, therefore, a prime object of the present invention to provide an off-loader which is versatile enough to permit widespread application in the clothing and softgoods industries.
It is a second object of the present invention to provide an off-loader which is versatile enough to be utilized with parts of a wide variety of different sizes, shapes and fabrics.
It is a third object of the present invention to provide an off-loader which is versatile enough to be used in conjunction with a wide variety of other materials handling equipment such as conveyors of different dimensions, or the like.
It is a fourth object of the present invention to provide an off-loader which is versatile enough to simultaneously accommodate variable numbers of parallel lanes of parts on the same or adjacent conveyors.
It is a fifth object of the present invention to provide an off-loader which is versatile enough to permit stacking of parts on interchangeable surfaces of different dimensions.
It is another object of the present invention to provide an off-loader which is designed for inexpensive modification to meet the needs of a particular purchaser.
It is still a further object of the present invention to provide an off-loader which can be adjusted by the purchaser, in an easy and quick fashion, to accommodate parts of different sizes, styles and fabrics and to permit same to accommodate variable numbers of lanes of parts.
It is still another object of the present invention to provide an off-loader which comprises relatively simple parts which function reliably together.
It is still a further object of the present invention to provide an off-loader which is relatively inexpensive to manufacture, modify and maintain.
In accordance with the present invention, apparatus is provided for off-loading a part from a conveyor or the like. The apparatus comprises a support and a part grabbing means. Means are provided for moving the grabbing means relative to the support in a given direction, from a first position, wherein the grabbing means grabs the part, through a second position, wherein the grabbing means releases the part, to a third position which is spaced from the second position along the same direction. Means are provided for adjusting the distance between the first and second positions so as to permit parts of a variety of different lengths to be accommodated.
The moving means comprises a means for mounting the grabbing means on the support and means for adjusting the position of the mounting means relative to the support. The support is preferably in the form of a housing or enclosure having an open entrance side designed to be situated adjacent the output end of a conveyor, along which one or more parallel lanes of parts travel.
A grabbing means and associated hardware is provided in alignment with each lane. The grabbing means is mounted to the undersurface of the top of the housing in a manner which permits the location of the grabbing means to be varied vertically with respect to the conveyor and horizontally in a direction substantially transverse to conveyor movement. In this manner, the height and position of the grabbing means can be varied to accommodate conveyors of different dimensions and several grabbing means can be utilized in side-by-side fashion within the same housing in order to off-load different numbers of parallel lanes of parts, either on one conveyor or on adjacent conveyors.
The moving means preferably comprises an assembly including guide means and a cylinder operably connected to the grabbing means for moving the latter along the guide means. The adjusting means comprises means for adjusting the position of the assembly relative to the support, as well as means for adjusting the position of the support relative to the conveyor.
Within the housing, a stacking surface is provided for each lane of parts which are off-loaded. The parts are stacked in succession on the stacking surface, which is at least partially located between the first and second positions of the grabbing means. The stacking surface is located below the path of movement of the grabbing means. In this manner, when the grabbing means grabs the leading end of the part in its first position, and then moves towards the third position, the free end of the part hangs from the grabbing means and is deposited on the stacking surface as the leading end is moved to the second position and released.
In order to prevent the free end of the part from contacting the previously stacked parts at a point too near the beginning of the path of movement of the grabbing means and thus causing alteration of the position of the part which is on the top of the stack, a means for temporarily supporting the free end of the part, until the grabbing means has traveled for a preset distance, is provided. This temporary support means is preferably in the form of a bar mounted transverse to the path of movement of the part a few inches below the first position of the grabbing means. After the part has been grabbed and the grabbing means begins to move away from the conveyor, the free end of the part, instead of hanging freely, is temporarily supported by the transverse bar until the grabbing means has moved along its path a distance which is somewhat less than the length of the part. The free end of the part is then no longer supported and is draped on the stack at a point close to its final position. Shortly thereafter, the leading end of the part is released by the grabbing means. In this manner, the parts, as same are put in succession on the top of the stack, will not vary the position of the parts previously situated on the stack.
Means are provided for adjusting the height of the stacking surface relative to the path of movement of the parts. In addition, means are provided for adjusting the angular position of the surface relative to the direction of conveyor movement and for accommodating stacking surfaces of different shapes and dimensions. Furthermore, the position of the stacking surface with respect to the housing, both in the direction of conveyor movement and in the direction transverse thereto, can be adjusted. This latter feature may be accomplished by mounting the stacking surface on rollers or the like. This configuration has the additional advantage of permitting the stacking surface, with the parts stacked thereon, to be rolled out of the housing and be replaced with an empty stacking surface.
The grabbing means comprises a pair of normally open jaws. A part sensing means is provided, as is a means responsive to the part sensing means for closing the jaws when a part is sensed to be between the jaws. The sensing means comprises a scanner including light generating means and photo-sensitive signal generating means, the latter being adapted to actuate jaw closing means and the moving means when the light path between the light generating means and the signal generating means is interrupted by the presence of the part between the jaws.
The scanner is preferably located above the jaws. The bottom jaw has a reflective surface thereon. Light from the light generating means travels from above the jaws to the reflecting surface on the bottom jaw and back to the photo-sensitive signal generating means. When the jaws are open and in the first position, the light path from the light generating means, to the reflective surface on the bottom jaw and then to the photo-sensitive signal generating means, is complete until interrupted by the presence of a part between the jaws. It is therefore necessary that the top jaw itself not interrupt the light path, falsely signalling the presence of a part between the jaws. In order to prevent the top jaw from inadvertently interrupting the light path, the top jaw is provided with a cutout portion adapted to be aligned with the light path. The light beam travels within the cutout portion, Part sensing may also be accomplished with a microswitch when the objects to be stacked are transparent or "open" such as netting.
In certain instances, the parts to be off-loaded are quite long. In fact, the part may be longer than the conveyor. In this case, the leading end of the part may be pulled by the grabbing means before the trailing end is freed from the work station feeding the conveyor. This situation obviously would create a problem. In order to overcome this problem, a delay means may be associated with the moving means for delaying the actuation of the moving means for a predetermined time interval after the light path is interrupted by the part. Thus, when the sensing means senses the presence of the leading end of a part between the jaws, the jaws are closed but actuation of the jaw moving means from the first position is delayed for a predetermined time during which the trailing end of the part is freed from the work station. This enables even very long parts to be stacked.